PubMed Health⌕ Search

Biomedical subjects

G Everett

Publications and source records attributed to G Everett.

At least 37 records · Page 2Linked to original sources
PubMed1981

Ecology of the free living stages of Nematodirus battus.

Eggs of Nematodirus battus placed on grass plots throughout the year were able to develop into infective larvae. In 1973 a large autumn peak was observed as well as the more usual subsequent spring peak. This was attributed to the weather conditions. The ability of the eggs to develop at all seasons is of importance in the survival of the parasite but not in the causation of clinical disease. Eggs washed out of the faeces into the soil develop quicker and suffer less mortality than eggs which remain trapped in the faecal pellets.

Animals↗
PubMed1978

Further observations on the effect of different levels of larval intake on the output of eggs of Ostertagia circumcincta in lambs.

Three groups of lambs were given 50, 250 or 2800 infective larvae of Ostertagia circumcincta per day for a period of six weeks. All groups then received 25,00 larvae per day for a similar period and observations were continued for a further six weeks. Egg output following the initial infection varied directly with the level of larval intake, but fell to a low during the second period of infection and decreased still further in the final six weeks of the observation. The investigation suggests that, provided high levels of residual larval infection on pasture are avoided, there appears to be considerable merit in exposing lambs to a low level of initial infection.

Animals↗
PubMed1977

The contribution of overwintering pasture larval infection and the spring rise as sources of Ostertagia circumcincta infection in lambs.

An investigation was made to study the acquisition of infection with Ostertagia circumcincta by lambs on land carrying residual infection, infection following the spring rise and both infections. Dry weather in June modified the usual pattern of herbage larval infection by delaying the peak of larvae derived from residual infection and cutting out the first half of the diphasic peak normally associated with the spring rise. It is suggested that prediction of the time when damaging infections develop on the herbage may be possible by a study of meteorological observations.

Animals↗
PubMed1976

The ecology of the free living stages of Nematodirus filicollis.

The development and survival of the eggs of Nematodirus filicollis placed on grass plots over a period of a year were studied. Development took place at every season although it was more rapid in the warmer months. Yields of larvae were highest from eggs placed outside during February, March and April. Larvae persisted for two to two and a half years after eggs were placed on the pastures. The extraordinary persistence of the eggs and larvae of N filicollis makes control of the parasite difficult.

Animals↗